Process of making acetanilid



HENRY CARL FEIIRLIN,

PATENT OFFICE.

OF ST. LOUIS, MISSOURI.

PROCESS OF MAKING ACETANILID.

SPECIFICATION forming part of Letters Patent No. 615,829, dated December 13, 1898.

Application filed April 25, 1898. Serial No. 678,793- (No specimens.)

To all whom it may concern.-

Be it known that I, HENRY CARL FEHRLIN, doctor of philosophy, a citizen of the Republie of Switzerland, residing at St. Louis, Stateof Missouri, have invented certain new and useful Improvements in Processes of Manufacturing Acetanilid, of which the following is a full, clear, and exactdescription, which will enable others skilled in the art to which it appertains to use the same.

Heretofore acetanilid has been made by boiling glacial acetic acid and anilin-oil in the usual well-known manner under a reflux condenser, or, as described in Letters Patent issued to F. N. A. Frerichs, dated July 20, 1897, No. 586,551, and another issued to Peter T. Austen and Herbert G. Tuttle, dated March 9, 1897, No. 613,311, from weaker acids and anilin-oil by heating same in autoclaves at a pressure of about fiftypounds, or, respectively, by distilling same while agitated and finishing the operation under diminished pressure.

The object, as set forth in the above patents, is to manufacture acetanilid from the commercial or weaker grades of acetic acid in place of the expensive glacial acetic acid. I have now discovered that another much more convenient and cheaper way of using these commercial acids is to manufacture the acetanilid by treating the anilin=oil with superheated vapors ofsuch acids and to simultaneously remove the water by the principle of dephlegmation. This process not only dispenses with many inconveniences resulting from the frequent leakages of autoclaves or of retorts under diminished pressure and does away with the mechanical agitators, (because a current of superheated vapors of acetic acid itself vigorously agitates the contents of the retort,) but my invention further affords an immense saving of time from the fact that acetic acid in its gaseous state acts much quicker upon anilin-oil than when the two materials are heated together in either one of the above-mentioned ways and that the reaction is much better finished-that is to say, that a certain or given amount of acetic acid thus acting upon anilin-oil converts a larger quantity of the latter into acetanilid than the same amount would convert in any one of the ways heretofore known, or,

in other Words,- that the crude product obtained in one operation contains much less anilin=oil than when it is made in any other way.

To carry out my process, I first heat the anilin-oil to about 160 Celsius and then pass a current of superheated vapors of as much acetic acid of a temperature of about 185 Celsius though the same as is necessary to convert the anilin-oil into acetanilid, taking care that the water contained in the acid and that produced by the reaction is continually removed by some suitable apparatus which acts by partially cooling the vapors, so that the stronger acetic acid and the anilin-oil are condensed and flow back into the retort, while a very weak aeiduous water and only a trifling amount of anilin-oil distil over.

The stronger the acetic acid employed for the distillation the sooner the formation of the acetanilid is completed; but my invention allows of the use of the lower grades of acetic acid as well and produces the acetanilid under all circumstances in a much shorter time and at a much lower cost than was heretofore possible.

I do not limit myself to the above-named conditions, for the process may, if desirable, be carried out under diminished pressure by connecting the apparatus with a vacuumpump. The duration of the operation is thus abridged very sensibly; but, as already inti mated,the inconveniences resulting from such an addition, to my experience, are a source of constant annoyance.

The greatest advantage of my invention consists in the readiness with which the gas eous acetic acid combines with anilin-oil, by the rapidity with which the water is expelled, and in the great economy derived from the necessity of the employment of only one retort, this latter advantage being still more apparent when it is considered that this process of manufacturing acetanilid can be combined with the refining or purifying acetanilid, as specified and carried out in another application filed by me, and thus afford a means of not only producing the crude acetanilid in only one retort, but also distilling pure acetanilid therefrom,thus carrying both the manufacture of crude acetanilid and the production of the pure product therefrom, as described in another application for patent filed by me on the 19th day of March, 1898, in one and the same apparatus.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is-- 1. The herein-described process of prod ucing acetanilid which consists in heating anilin-oil to about 160 Celsius and subjecting the same to the action of a current of superheated vapors of acetic acid of a temperature of 185 Celsius and simultaneously removing the water until the conversion of the anilinoil into acetanilid is satisfactorily completed.

2. The herein-described process of producing acetanilid which consists in heating anilin-oil and subjecting the same to the action of a current of superheated vapors of acetic acid, and simultaneously removing the Water until the conversion of anilin-oil into acctanilid is satisfactorily completed.

3. The herein-described process of producing acetanilid which consists in heating the anilin-oil with the superheated vapors of acetic acid and simultaneously removing the wa ter until the anilin-oil is satisfactorily converted into acetanilid.

In testimony whereof I affix my signature in the presence of two witnesses.

HENRY CARL FEIIRLIN.

lVitnesses:

ALFRED A. MATHEY, C. F. KELLER. 

